The invention relates to a socket of the type adapted to receive a lamp or other load device having a threaded cylindrical shell serving as one contact, and a center contact or eyelet serving as the other contact. Lamp bases of this kind are very common, come in various sizes and are generally referred to as Edison screw bases, and the sockets therefor are available in matching sizes. For ordinary domestic sizes of incandescent lamps, the medium screw base is generally used, while for industrial applications and high intensity discharge (HID) lamps, the mogul screw base is generally used.
When an HID lamp such as a metal halide or a high pressure sodium discharge lamp is extinguished, the high vapor pressure in the arc tube prevents immediate restarting at normal voltage and a cooling interval is required. This enforced temporary outage may last from about 1 minute up to as much as 15 minutes depending upon lamp type. Circuits for quickly restarting extinguished lamps while still hot, commonly referred to as "hot restart circuits," have recently become available, one such being described in U.S. Pat. No. 4,331,905-Owen, Starting and Operating Circuit for Gaseous Discharge Lamps, issued May 25, 1982, whose disclosure is incorporated herein by reference. In hot restart luminaires utilizing such a circuit, the voltage in the lamp socket on open circuit includes pulses in the range of 5,000 to 6,000 volts at high frequencies, for instance at 20,000 hz. Such voltages are hazardous and a person replacing the lamp when power is on runs the risk of shock or burn.